Support func foo(nonescapingClosure: () -> Void)

[dafurman]

Thanks for the work you've done on this library! As someone who loves Sourcery mocks, it's no surprise someone would take advantage of Swift Macros to reimplement that functionality, so thanks for being that person!

Anywhoo, this is from the main branch as of today.

functions with nonescaping closures will cause Spyable to fail to compile, whereas escaping closures compile just fine:

As a sidenote, it also seems like indentation is off at lines 9 & 22.

For reference: The code generated in Sourcery's Automockable for the same protocol is this, which compiles:

class MyProtocolMock: MyProtocol {

    //MARK: - doThing

    var doThingCompletionCallsCount = 0
    var doThingCompletionCalled: Bool {
        return doThingCompletionCallsCount > 0
    }
    var doThingCompletionReceivedCompletion: ((() -> Void))?
    var doThingCompletionReceivedInvocations: [((() -> Void))] = []
    var doThingCompletionClosure: ((@escaping () -> Void) -> Void)?

    func doThing(completion: @escaping () -> Void) {
        doThingCompletionCallsCount += 1
        doThingCompletionReceivedCompletion = completion
        doThingCompletionReceivedInvocations.append(completion)
        doThingCompletionClosure?(completion)
    }

    //MARK: - doThing

    var doThingNonescapingCompletionCallsCount = 0
    var doThingNonescapingCompletionCalled: Bool {
        return doThingNonescapingCompletionCallsCount > 0
    }
    var doThingNonescapingCompletionClosure: ((() -> Void) -> Void)?

    func doThing(nonescapingCompletion: () -> Void) {
        doThingNonescapingCompletionCallsCount += 1
        doThingNonescapingCompletionClosure?(nonescapingCompletion)
    }
}

It looks like this could be resolved by making spyable match automockable's behavior by having these two lines be removed for nonescaping closures:

doThingNonEscapingCompletionReceivedNonEscapingCompletion = (nonEscapingCompletion)
doThingNonEscapingCompletionReceivedInvocations.append((nonEscapingCompletion))

Automockable.stencil has lots of checks that go something like if x and not hasNonEscapingClosures, so maybe something similar could be replicated here?